This recone kit works for one of the speakers in the SA1521 cabinet. There were multiple woofers used so verify that you have the one with the 3″ voice coil in order to use this kit. Genuine Mackie (RCF) kit is no longer available. Aftermarket parts are also availalbe in 4 ohms and 16 ohms and in 2.5″ voice coil 8 ohm, 4 ohm and 16 ohm versions.